1. Field of the Invention
The present invention relates generally to hand tools for smoothing-out pastey and plastic substances on planar surfaces, and more specifically to wipe-down knives for smoothing wet plaster and other finishing compounds during drywall construction.
2. Description of the Related Art
In the phase of residential and commercial building construction in which the interior wall surfaces are applied to supporting studs, sheet rock panels are nailed or screwed to the studs and then the seams therebetween are taped-over and plastered. After tape and plaster are applied to the seams, the surface of each seam must be wiped-down to give it a finished surface appearance and to prepare it for the application of paint.
The wipe-down phase of drywall construction is commonly carried out with the use of a short hand trowel. However, using a hand trowel for wipe-down purposes has many drawbacks. For example, most hand trowels have a relatively short blade which requires the user to make multiple horizontal passes back and forth across the seam to yield a ridge-free seam surface appearance. Further, on walls where the ceiling height is over eight feet, or so, the user must climb upon a ladder, scaffold or other apparatus to reach and wipe-down the seams.
Various long-handled trowels have been proposed, but these are generally clumsy and more difficult to control as their handles get longer. And, despite their long handles, it is difficult to apply the blade of a long-handled trowel to a wall surface at the proper angle to smooth-out plaster.
The apparatus of U.S. Pat. No. 4,817,229 issued to Sedillo in 1989, comprises a swiveling, short-edged, semicircular-shaped trowel blade on a long handle pole for wiping-down high seams. Sedillo's apparatus attempts to address the problem of achieving the correct blade-to-wall angle when using a long-handled trowel, but it is difficult to use and lacks the durability the journeyman drywall specialist would normally expect of his or her tools. Further, Sedillo's short blade makes it necessary to use a great many individual strokes in smoothing out a plaster surface. This makes it difficult to avoid telltale ridges between strokes.
Several long-bladed trowels have been proposed for the purpose of reducing the number of strokes required to finish a plaster surface. However, those constructed of metal are too heavy and not sufficiently flexible because, when thinner sheets of metal are used, these tend to deform upon being bolted as securely as necessary to an elongate blade-supporting bar. Securely bolting a thin metal blade along one edge tends to warp the opposing edge and make it wavy; this results in a wavy pattern in the plaster surface being worked. The same has been found in experimenting with over-sized plastic blades.
Thus, it appears that a need exists for a wipe-down knife fit for use in all drywall seam-finishing operations, no matter the height of the wall being finished.